When Japan bombed Pearl Harbor on December 7, 1941, the United States quickly declared war on the Empire of Japan. Nine weeks later, President Franklin D. Roosevelt issued Executive Order 9066 which gave the War Department the authority to define military areas in the West Coast states and to exclude anyone who might threaten the war effort. The United States Government then made a controversial decision to imprison most of the 120,000 Japanese Americans living on the West Coast of the United States, 77,000 of whom were American citizens. The remainder were registered aliens of Japanese ancestry, many of whom had lived in the United States for years.

The Japanese Americans were moved inland to ten permanent camps in isolated parts of the American West. The camps were surrounded by barbed wire and were complete with guard towers and armed guards. There were permanent camps in California, Arizona, Idaho, Utah, Wyoming, Colorado, and Arkansas. There were also dozens of other assembly areas and temporary camps. The evacuation began on March 25, 1942, and by August 12, 1942, almost all Japanese Americans were imprisoned.